For FF applications, it is generally more desirable to have a 1.0 way setup.
This is because during decel and braking, you want the diff to be open and free for both wheels to spin at different speeds. If there is any locking such as the 1.5 way would enable, the car would understeer more than it already does because the front wheels are being forced to rotate at similar speeds while turning.
For those who are not that experienced on circuit, the 1.5 way may be faster than a 1.0 way to begin with as it provides a little margin of safety in form of understeer, which is easier to control for beginners than a sudden oversteer situation.
The initial lock/response from KAAZ/Spoon is set very high which is why the clunking is quite severe at low speeds; the loss of lock will decline much faster as the plates are constantly under pressure and will wear faster as a result - not to mention a lot more heat is generated inside the trans. Cone washers are used to push the plates together constantly which provides the lock and because the initial response is so high, this is what causes the diff to lock immediately in the rain.
Our diff is similar to the Cusco RS which uses springs to activate the locking/initial response. This initial setting is adjustable by adding or increasing the number of springs.
In general, it is desirable to have a lower initial lock so the car doesn't hunt all over the place in the rain and also makes the car easier to handle because the lock is not as abrupt.
This is also better for all surrounding components such as the CVs and the driver's sanity!
http://www.motoiq.com/MagazineArtic...Project-EJ-Civic-Building-the-Drivetrain.aspx